1. Field of the Invention
The present invention relates to a method for controlling the temperature in the chamber of an exposure apparatus used in a photolithography process for producing a semiconductor element, an imaging element (CCD, etc.), a liquid crystal display element, a thin film magnetic head, etc., and to an exposure apparatus operated in the method.
2. Description of the Related Art
When a semiconductor element, etc. is produced, an exposure apparatus which transfers a pattern of a reticle as a mask to each shot area on the wafer to which resist is applied as a photosensitive substrate directly or through a projective optical system. Conventionally, an exposure apparatus (stepper) of a contraction projection type in a step-and-repeat system has been widely used as an exposure apparatus. However, a projective exposure apparatus in a step-and-scan system for synchronously scanning the reticle and the wafer for the projective optical system for exposure has recently arrested attention.
FIG. 1 shows the general configuration of a conventional exposure apparatus.
In FIG. 1, for example, a semiconductor element can be formed by overlapping for exposure a multiple-layer circuit pattern on a wafer 6 in a predetermined arrangement. Therefore, in the process of exposing the wafer 6, it is very important to improve the precision in alignment between the pattern image to be exposed and the existing pattern on the wafer 6, and the precision in controlling a focus position. Therefore, the exposure apparatus has an isolation room called a xe2x80x98chamberxe2x80x99 which is controlled such that the temperature in the exposure apparatus can indicate a constant value, and contains the body of an exposure device including precision parts such as a projective optical system 5, a stage, etc. The body of the exposure device includes a lighting optical system 2, a reticle stage 4 for holding and aligning a reticle 3, the projective optical system 5, and a wafer holder 7 for holding the wafer 6, and a wafer stage 8 for aligning the wafer 6 (the wafer holder 7). The wafer stage 8 is mounted on the floor of the chamber 1 through a frame material 9. The chamber 1 is mounted on a floor F1 in a semiconductor factory.
To keep a constant temperature in the chamber 1, a fluid supply device 11 is provided in the chamber 1. The fluid supply device 11 is equipped with a cooler 13 and a heater 14, introduces the air outside or inside the chamber 1, controls the temperature at a constant value by the effect of the cooler 13 and the heater 14, and supplies the air into the chamber 1. The cooler 13 compresses and liquidizes a coolant by a compressor, etc., cools the air with evaporation heat, and has a power source such as a motor, etc. for operating the compressor. Each of the parts such as a stage provided in the chamber 1 is considerably heavy, and requires a high-speed operation, thereby largely heating each of them. Accordingly, the fluid supply device 11 of the chamber 1 is requested to maintain a strong cooling ability, thereby requiring a large compressor of the cooler 13.
In addition, to prevent fine dust harmful in transferring a circuit pattern from being lead into the chamber 1, the temperature-controlled air is to be supplied to the chamber 1 through a dust filter 21 such as a HEPA filter (high efficiency particulate air-filter). Therefore, the compressor formed by a pressure fan 12 for a blow and a motor is required to output pressure strong enough to pass the air blow through the dust filter 21. As a result, a large pressure fan 12 and a large motor are used.
FIG. 2 shows the general configuration of another conventional exposure apparatus.
The exposure apparatus shown in FIG. 2 is different from the exposure apparatus shown in FIG. 1 in that the fluid supply device 11 is not mounted in the chamber 1, but on the external wall of the fluid supply device 11. Otherwise, they have the same configuration. That is, each of them includes the lighting optical system 2, the reticle stage 4 for holding and aligning the reticle 3, the projective optical system 5, the wafer holder 7 holding the wafer 6, the wafer stage 8, the frame material 9, etc. in a constant temperature room 100. In addition, the exposure apparatus shown in FIG. 2 is the same as that shown in FIG. 2 in that the fluid supply device 11 has the pressure fan 12, the cooler 13, and the heater 14, and blows into the constant temperature room 100 by passing the temperature-controlled air through the dust filter 21 to control the temperature in the chamber 1. The chamber 1 provided with the fluid supply device 11 is mounted on the floor F1 in the semiconductor factory.
Furthermore, a device has been developed not only to maintain a constant temperature in the chamber 1, but also to supply a fluid at a constant temperature to a specific local area (a coil portion of a linear motor, etc.) of an exposure apparatus so that the portion can be more effectively temperature-controlled.
As described above, the conventional exposure apparatus includes the fluid supply device 11 in the chamber 1 or on the external wall of the chamber 1. As a result, the vibration generated during the operation of the fluid supply device 11 unfavorably lowers the precision in alignment, etc. of the exposure apparatus.
That is, the vibrations generated by the compressor of the cooler 13 forming part of the fluid supply device 11, and the pressure fan 12 and the motor of the compressor vibrate the wafer stage 8 of the wafer 6, thereby deteriorating the alignment precision of the wafer 6, and also the overlapping precision, or vibrate the projective optical system 5 to lower the contrast of the transferred image.
In the conventional exposure apparatus, since the vibration of the fluid supply device for a chamber 1 during the operation has a minor influence with the requested precision taken into consideration, thereby generating a serious problem. However, with an increasing number of smaller semiconductor integrated circuits, etc., the influence of the vibration cannot be ignored because the alignment precision, etc. requested to the exposure apparatus becomes more strict.
The present invention has been developed based on the above described background, and aims at the first object of providing a method of controlling the temperature in a chamber of an exposure apparatus having the body of an exposure device, and a method of controlling the temperature to reduce an unfavorable influence from the vibration caused by the temperature control. Furthermore, the present invention aims at the second object of providing an exposure apparatus capable of using the above described temperature control method.
In the temperature control method according to the present invention is used with a chamber (1) containing the body of an exposure device for transferring a mask pattern to the substrate, a fluid (a gas, a liquid) supplied to the chamber (1) from a fluid supply device (11, 11A, 11B) provided independent of the chamber (1) is output, supplied from the fluid supply device (11, 11A, 11B), and is temperature-controlled before supplied into the chamber (1).
With the present invention, the temperature in the chamber can be controlled by controlling the temperature of a fluid supplied to the chamber. Thus, the temperature adjustment equipment, which has been in a chamber as a vibration source, can be mounted outside the chamber, thereby removing the vibration source from the chamber. In addition, since the vibration during the temperature-control of the fluid is hardly transmitted into the chamber, an unfavorable influence such as the deterioration in the alignment precision in the body of the exposure device causing the vibration can be reduced.
Furthermore, in the exposure apparatus according to the present invention, the body of an exposure device for transferring a mask pattern to the substrate is provided in the chamber (1). The exposure apparatus has a fluid supply device (11, 11A, 11B) mounted outside the chamber, and supplies a temperature control fluid into the chamber (1). With the above described present invention, the vibration of the fluid supply device (11, 11A, 11B) for outputting a temperature control fluid is hardly transmitted into the chamber (1), the temperature control method according to the present invention can be used almost successfully.
In this case, it is desired that the present invention includes a temperature control device (18, 24, 43) for controlling the temperature of the fluid output from the fluid supply device (11, 11A, 11B), and transmitting the fluid into the chamber (1), thereby controlling the temperature in the chamber (1) at a predetermined temperature. At this time, since the temperature control device (18, 24, 43) controls the temperature of the fluid transmitted into the chamber (1), the temperature control method according to the present invention can be applied.
Furthermore, the final control of the temperature of the fluid led to the chamber (1) is not performed by the fluid supply device (11, 11A, 11B) located away from the chamber, but by, for example, the temperature control device (18, 24, 43) located near the constant temperature room in the chamber (1). Therefore, although the fluid supply device (11, 11A, 11B) is distant from the chamber (1), the feedback loop of the temperature control is not elongated, and the temperature in the chamber (1), or the temperature of the fluid used in the chamber (1) can be maintained precisely at a predetermined level. Thus, the body of the exposure device of a projective optical system (5), a stage system (4, 8), etc. is maintained at a constant temperature, thereby realizing a precision exposure apparatus with little vibration.
In this case, it is desired that the fluid supply device (11, 11A, 11B) includes a fluid supply device (13-14, 13-14a-14b) for controlling the temperature of the fluid. The level of the temperature control by the temperature control device (18, 24, 43) located near the chamber (1) is low when the temperature of the fluid to e supplied to the chamber (1) is roughly controlled by the fluid supply device (13-14, 13-14a-14b), thereby easily designing the temperature control device (18, 24, 43) using a heater without a vibration source or temperature control elements such as a Peltier element (18), and reducing the vibration in the chamber (1).
A liquid supply device (11A) outputs, for example, a plurality of fluids at different temperatures, and a temperature control device (24) mixes the plurality of fluids at a predetermined ratio. A fluid at a desired temperature can be obtained by controlling the mixing ratio of the plurality of fluids at different temperatures.
In addition, it is desired that the present invention further includes a detector (19) for detecting the temperature of the fluid controlled by the temperature control device (18, 24, 43), and at least one of the temperature control device (18, 24, 43) and the fluid supply device (13-14, 13-14a-14b) controls the temperature of the fluid based on the detection result of the detector (19). The control precision of the temperature in the chamber (1) can be improved by feeding back the temperature of the detector (19) mounted together with the chamber (1).
Furthermore, it is desired that the fluid supply device (11, 11A, 11B) is mounted on the floor different from the floor on which the chamber (1) is mounted. Thus, the vibration of the fluid supply device (11, 11A, 11B) is not transmitted into the chamber (1).
It is also desired that the fluid supply device (11, 11A, 11B) is designed such that the vibration of the fluid supply device (11, 11A, 11B) cannot be transmitted to the body of the exposure device.
In the exposure apparatus according to the present invention, the body of the exposure device for transferring a mask pattern on the substrate is mounted in the chamber (1) controlled for a predetermined temperature, and the fluid machinery room (11, 11A, 11B) for controlling the temperature in the chamber (1) is mounted under the floor on which the chamber (1) is mounted. In the second exposure apparatus, the vibration during the temperature control of the machinery room (11, 11A, 11B) is not transmitted into the chamber (1), thereby reducing the unfavorable influence caused by the vibration in the body of the exposure device such as the deterioration in alignment precision, etc.
The exposure system according to one aspect of the present invention includes: a chamber containing the body of an exposure device which forms a pattern on a substrate; a first temperature control unit, mounted separate from the body of the exposure device, for controlling the temperature of a fluid taken through the body of the exposure device; and a second temperature control unit, connected to the first temperature control unit, for controlling the temperature of the fluid taken through the first temperature control unit, and supplying it to the body of the exposure device. The second temperature control unit has a control ability different from that of the first temperature control unit.
The exposure system according to another aspect of the present invention includes: a chamber containing the body of an exposure device which forms a pattern on a substrate; and a fluid supply device, mounted on a plane different from the plane on which the chamber is mounted, for supplying a fluid into the chamber.
The exposure system according to another aspect of the present invention includes: a chamber containing the body of an exposure device which forms a pattern on a substrate; and a fluid supply device, mounted separate from the body of the exposure device, for supplying a fluid into the chamber. At least one of the chamber and the fluid supply device is mounted using a vibration-proof material
The temperature control method according to another aspect of the present invention controls the temperature in a chamber containing the body of an exposure device which forms a pattern on a substrate. In this method, a first temperature control unit mounted separate from the body of the exposure device controls the temperature of a fluid taken through the body of the exposure device, and a second temperature control unit having a control ability different from that of the first temperature control unit controls the temperature again of the fluid taken through the first temperature control unit, and then supplies the fluid to the body of the exposure device.
The temperature control method according to another aspect of the present invention controls the temperature in a chamber containing the body of an exposure device which forms a pattern on a substrate. In this method, a fluid supply device mounted on a plane different from a plane on which the chamber is mounted supplies a fluid whose temperature has been adjusted into the chamber.
The temperature control method according to another aspect of the present invention controls the temperature in a chamber containing the body of an exposure device which forms a pattern on a substrate. In this method, a fluid supply device mounted separate from the body of the exposure device supplies a fluid whose temperature is adjusted to the chamber. At least one of the chamber and the fluid supply device is mounted using a vibration-proof material.
The exposure system producing method according to another aspect of the present invention produces an exposure system, and includes: a chamber containing the body of an exposure device which foims a pattern on a substrate; a first temperature control unit, mounted separate from the body of the exposure device, for controlling the temperature of a fluid taken through the body of the exposure device; and a second temperature control unit, connected to the first temperature control unit, for controlling the temperature of the fluid taken through the first temperature control unit, and supplying it to the body of the exposure device. The second temperature control unit has a control ability different from that of the first temperature control unit.
The exposure system producing method according to another aspect of the present invention produces an exposure system, and mounts on a predetermined plane a chamber containing the body of an exposure device which forms a pattern on a substrate, and mounts on a plane different from the plane of the chamber a fluid supply device for supplying a fluid to the chamber.
The exposure system producing method according to another aspect of the present invention produces an exposure system, includes a chamber containing the body of an exposure device which forms a pattern on a substrate, and mounts a fluid supply device for supplying a fluid to the chamber separate from the body of the exposure device using a vibration-proof material.
The exposure system producing method according to another aspect of the present invention produces an exposure system, mounts using a vibration-proof material a chamber containing the body of an exposure device which forms a pattern on a substrate, and mounts a fluid supply device for supplying a fluid to the chamber separate from the body of the exposure device.
The exposure system according to another aspect of the present invention includes: a chamber, mounted on a predetermined plane, containing the body of an exposure device forming a pattern on a substrate; a fluid supply device, mounted separate from the body of the exposure device on the same plane, for supplying a fluid to the chamber; and a connection material mounted between the chamber and the fluid supply device, for connecting the chamber and the fluid supply device such that the fluid can be transmitted between the chamber and the fluid supply device. The exposure system is designed to prevent the vibration generated by the fluid supply device during the operations from being transmitted to the body of the exposure device.
The temperature control method according to another aspect of the present invention controls the temperature in a chamber containing the body of an exposure device forming a pattern on a substrate. In this method, a fluid whose temperature is adjusted is supplied to the chamber from a fluid supply device mounted to the chamber through a connection material on the same plane as the chamber. Thus, the vibration generated by the fluid supply device during the operations is not transmitted to the fluid supply device.
The exposure system producing method according to another aspect of the present invention produces an exposure system, includes on a predetermined plane a chamber containing the body of an exposure device which forms a pattern on a substrate, and mounts on the same plane a fluid supply device for supplying a fluid to the chamber separate from the body of the exposure device. A connection material for connecting the chamber to the fluid supply device is provided between the chamber and the fluid supply device so that the fluid can be transmitted between the chamber and the fluid supply device. The exposure system is designed to prevent the vibration generated by the fluid supply device during the operations from being transmitted to the body of the exposure device.
According to the present invention described above, the vibration of the fluid supply device for providing a fluid for temperature control is hardly transmitted into the chamber, thereby realizing the exposure system using the temperature control method of the present invention.
Since the fluid supply device for supplying a temperature control fluid and its chamber are mounted on different floors according to the present invention, the vibration is hardly transmitted between them, thereby realizing the exposure system using the temperature control method of the present invention.
Since the vibration-proof material is applied to prevent the vibration from being transmitted between the fluid supply device for supplying a temperature control fluid and the chamber, the vibration is hardly transferred, thereby realizing the exposure system using the temperature control method of the present invention.
According to the present invention, since the fluid supply device for supplying a temperature control fluid is located away from the chamber by the distance for attenuation of 25% (6 dB) or more of the vibration, the vibration is hardly transmitted, thereby realizing the exposure system using the temperature control method of the present invention.
According to the present invention, the vibration of the fluid supply device for supplying a temperature control liquid is hardly transmitted to the chamber, thereby realizing the temperature control method of the present invention.
According to the present invention, since the fluid supply device for supplying a temperature control fluid and the chamber are mounted on different positions, the vibration is hardly transmitted, thereby realizing the temperature control method of the present invention.
According to the present invention, since there is a vibration-proof material to prevent the vibration from being transmitted between the fluid supply device for supplying a temperature control fluid and the chamber, the vibration is hardly transmitted, thereby realizing the temperature control method of the present invention.